Here is small section that touches on the main argument of the article:

The trickster tale in Western scholarship has a number of characteristics relevant to the study of the marketing of breakfast cereals. First, the primary motivating force that drives the dramatic action of many trickster tales is the acquisition of something—sometimes a valued magical object, but frequently only the desire for food. This perpetual hunger often takes on a predatory character. For example, Uncle Remus tales often center around the efforts of Brer Fox to eat Brer Rabbit, and a good number of the Winnebago trickster tales have Wakjunkaga manipulating his victims into providing him with a ritual feast, or falling into a trap where they can be killed and eaten. As William Hynes puts it, "Most tricksters are forever hungry and in search of food. No prohibition is safe from the trickster, especially if it lies between the trickster and a prospective meal" (42). Trickster-style breakfast cereal advertising universally takes the competition-for-valued-food motif as its plot premise, with the valued object or desired food substance represented—of course—by the breakfast cereal. Like the tricksters of myth, the cereal tricksters are forever hungry for the cereal product, and willing to stalk, steal, deceive, and engage in various forms of predation in order to get it.

The breaking of taboo, usually by the trickster figure, is a motif so widespread in trickster tales that some scholars—for example, Laura Markarius—argue that it constitutes the major mythic function of trickster characters (68). The taboos broken by folkloric tricksters are generally more extreme than those of cereal tricksters, as when the Japanese Susa No-o commits incest with his sister, the Algonquian Manabozo chooses a wife from the menstrual hut, or the Tibetan Uncle Tompa drops feces in the king's lap. Yet, the dynamic is also apparent more subtly when, for example, child characters in Kix and Life cereal commercials break the taboo against eating cereals defined by adults as "healthy," and the dramatic outcome rewards the forbidden behavior.3 As demonstrated later, advertising that uses the competition-for-food or predation motifs may often exhibit violations of taboos against stealing. Cannibalism and inappropriate predation are also common taboo-breaking motifs in trickster tales, and some cereal advertising exhibits undertones of these deviations. Breakfast cereals such as the General Mills monster cereals and Kellogg's Frosted Mini-Wheats, in which the mascot takes the form of the cereal itself, dramatize these patterns by placing acquisition of the magical benefits of the cereal in symbolic consumption of the mascot.

Disguise and/or mistaken identities are another prevailing motif in trickster tales. Wakjunkaga is mistaken for a shaman when he gets his head stuck in an elk skull or dresses up as a woman in order to seduce the chief's daughter and get the wedding feast (Radin 23). Hermes disguises himself as a mortal—along with Zeus—at the house of Baucis and Philemon (Doty 61). The Tibetan Uncle Tompa dresses in the clothing of a nun so that he can enter a convent and make love to all the nuns there (Hynes 36). The disguise motif holds true in breakfast cereal advertising as well, with the cereal-trickster often using the disguise as a means to get the valued substance (cereal) away from its rightful owners. Many scholars see the disguise motif as an outgrowth of the trickster figure's own polymorphous or undefined form. Particularly in North America, tricksters move fluidly between animal and humanoid forms and body parts have a tendency to change size or operate independently when detached. A motif that is therefore related to the disguise/identity change often seen in trickster tales, and in cereal commercials, is the transformation of the trickster himself or others into different forms.

I think children are especially attracted to trickster figures, which is why (I would presume) they have become one of the most prevalent motifs in teaching stories from a variety of cultures. The trickster teaches what can happen when taboos are broken for selfish reasons, often in a humorous way, but nearly always with a bad outcome.

The article uses the Trix Rabbit as one of its main examples. "Silly rabbit, Trix are for kids!" Who doesn't know that line from childhood?

In his basic form, the Trix Rabbit resembles mythical trickster figures in that he is an anthropomorphized animal, like the hare trickster Wakjunkaga. He exhibits the insatiable hunger typical of Wakjunkaga, but not for foods typically associated with rabbits. He desires only the Trix brand breakfast cereal, and is willing to cheat and deceive in order to get it. In the early days of Trix, the variations on the specific disguise that the Rabbit adopted were still closely identified with the plot premise: He was attempting to appear as something other than a rabbit, so a little old lady or astronaut disguise would do. In more recent years the disguises have begun to take on the form of whatever the advertisers perceive as popular with kids at the time, so in the 1980s the Rabbit disguised himself as a breakdancer, and, most recently, a karaoke singer. In any case, the Rabbit is using these disguises, to appear more human than rabbit, which emphasizes the way in which the Trix Rabbit most closely corresponds to the archetypal Radin/Jung trickster.

Jung, in particular, theorized, in a now largely discounted but still interesting way, that the trickster figure represents the psychological state of humanity making the transition from animal to human. Using Radin's description of Wakjunkaga as a touchtone, Jung describes the trickster cycle as demonstrating how the trickster gradually comes to greater levels of control over his selfish, predatory, animalistic impulses—associated with animal physical forms such as the hare, the coyote, and the raven. In this way, according to Jung, Radin's trickster evolves into a thereomorphic culture hero who sacrifices himself to give gifts to humankind, which is the hallmark of humanity in this scheme (144). The Trix Rabbit fits right into this design, not only in the way that his animal form matches that of the Winnebago Indian Hare that Radin studied, but also in the symbolic pattern of his advertisement narratives. The Rabbit desires the Trix cereal, which represents the outward sign of humanity: "Trix is for kids." He disguises himself as a kid, taking on the superficial form of a human in an attempt to make the transition. But the disguise is unable to conceal his baser selfish impulses—which manifest as frenzied enthusiasm—and his true animal nature is revealed to the kids who take away the magical humanizing substance. Whether or not one gives credence to the impact of Jungian depth psychology on the communal consciousness, the cyclical tragic drama played out over and over again produced a verifiable impact in at least one case. In the 1980s there arose such a public outcry about the Rabbit's plight that General Mills held an election allowing kids to vote on whether the Rabbit should be allowed to finally get the Trix. The vote came out in the Rabbit's favor, and he was rewarded with three spoonfuls of the cereal—although his advertisements then immediately reverted to the old formula.

I still think what is being overlooked here, even if we allow the Jungian interpretation (which I do, with reservations and corrections), is that the trickster is ALWAYS an example of bad behavior and its outcomes -- these are teaching stories. The rabbit doesn't get any Trix because he acts impulsively and selfishly, often using deception (and because he is a rabbit and Trix are for kids, which reinforces the special nature of Trix as human food).

Still, when Green starts getting to his main point, I agree with him completely:

So, bearing all this in mind, a rationale for trickster figures into cereal advertisements begins to emerge. From the time of their origins, cereals have never been presented as just food, but have always been closely associated with the mysticism of health, healing, and generation—and, by extension, with moral goodness. As the substance that symbolically endows humanity with these qualities, it is only natural that the culture hero—whose body and generative spirit are closely identified with the substance—would bequeath it to humankind, or that the selfish trickster would wish to hoard or steal it all for himself. The unique history and development of breakfast cereal coincides with their use of mythological and mystical symbolism. Whatever persuasive power such myths arguably have, the advertising that uses such myths can be said to draw additional influence and authority from the associations. Cereals are parity products,5 and advertisers are severely limited in the allowable claims of superiority for one over another. Investing some outwardly distinctive feature of their own cereal with mystical properties, and placing that created value at the center of a mythic quest drama tends to work around this limitation.

What makes these figures ideal salespeople is that they seek the magic food, the elixir of life. The whole motif of "magical food" and the use of the trickster appeals to the pre-rational minds of children (and some adults). This approach sets up a dynamic in which the cereal becomes desirable to children as some kind of coveted item.

In reality, I think this pattern is changing to a degree. Children are much more sophisticated now than when I was a naive little lad. The article mentions near the end that the market has been transformed in the past 15 or 20 years. The old mainstay characters are still there, but I don't think the characters or the motifs carry as much currency as they once did.